1. Field of the Invention
The present invention relates to an apparatus and method for selecting antennas and nodes so that communication capacity and the reliability of a link during communication between multiple-input multiple-output (MIMO) wireless nodes equipped with two or more antennas (i.e., an array antenna) can be maximized.
2. Description of the Related Art
Multi-input multi-output (MIMO) technology can achieve spatial multiplexing gain and can thus enhance the communication capacity during communication between nodes equipped with array antennas. However, such spatial multiplexing gain can result in high link failure rates due to the deteriorating quality of received signals caused by the shadowing effect. In a MIMO communication system, spatial multiplexing gain can be achieved when small-scale fading factors of antennas of a node are statistically uncorrelated. Accordingly, as the number of antennas provided to a transmission node or a reception node increases, communication capacity linearly increases. However, as the degree of correlation between small-scale fading factors increases, communication capacity decreases. In addition, when the shadowing effect is caused by an obstacle such as a building that blocks the path of reception of signals, spatial multiplexing gain cannot be obtained.
Therefore, it is necessary to develop techniques capable of addressing the problem caused by the shadowing effect, i.e., the problem of low signal reception sensitivity of MIMO nodes equipped with multiple antennas and achieving the advantage of MIMO technology regarding spatial multiplexing gain.